1,    a,    adults,    anatids,    animals,    aves,    beaks,    bills,    birds,    cleaning,    cleans,    format,    lakes,    laterally,    move,    movement,    moves,    open,    outdoors,    outside,    preening,    preens,    river,    solo,    swans,    swimming,    swims,    waterbirds,    waterfowls,